5907899
Descripción
Fichas por Isabel van der Hoorn, actualizado hace más de 1 año
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Creado por Isabel van der Hoorn
hace más de 8 años
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| Pregunta | Respuesta |
| What does an atom consists of? | Nucleus that contains protons and neutrons and electrons that occupy the outer shells |
| What are protons? | Positive, found in nucleus, relatively heavy |
| What are neutrons? | Neutral, found in nucleus, relatively heavy |
| What are electrons? | Negative, found in outer shells, really small mass |
| What is the charge on an atom? | An atom is always electrically neutral. Therefore the number of protons equals the number of electrons. |
| What is an atomic number? | This is the number of protons in the nucleus of the atom. The atomic number determines the nature of the element. |
| What is a mass number? | This is the total number of protons and neutrons in the nucleus. |
| What is an isotope? | Atoms of the same element which have the same number of protons in the nucleus but a different number of protons. |
| What is the stable electron arrangement in the outer shells? | 2,8,8 |
| Why are inert gases chemically inert? | Because they have very stable electron arrangements. |
| What is Group 1? | Alkaline Metals, highly reactive with water and air. They have a charge of +1. Such as Lithium and Sodium. |
| What is Group 2? | Alkaline Earth Metals. Less reactive than Group 1 but share many properties. Charge of +2. Such as Berylium and Magnesium. |
| What is Group 17? | Contains the halogens. Highly reactive and poisonous non-metals. Charge of -1. Such as Fluorine and Chlorine |
| What is Group 18? | Contains the inert gases which are very unreactive as they have full outer shells. Such as Helium and Argon. |
| What are the horizontal rows called? | Periods |
| What are ions? | An ion is a charged atom or group of atoms. Atoms lose or gain electrons to get a full outer shell. Ions are more stable than the atoms that formed them. |
| Charges on ions? | A positive ion is formed when electrons are lost. A negative ion is formed when electrons are gained. |
| What are the charges on metal ions? | Positive. |
| What is a compound? | A compound contains two or more elements joined together chemically. |
| What is an ionic compound? | Ionic compounds are formed between metal and non-metal elements. |
| How is an ionic compound formed? | The metal atom gives electrons to the non-metal atom so that each atom has a stable structure. |
| What is an ionic bond? | The strong force of attraction between opposite charges on the ions. |
| What structure are ionic compounds always found in? | Ionic compounds have strong electrostatic bonds between the ions. These bonds are fined in a 3D lattice structure. They require a lot of energy to break and therefore have high melting/boiling points. |
| What does the ending -ide indicate? | That there are only two elements in the compound. |
| What does the ending -ate indicate? | That the compound contains oxygen. |
| What does the ending -ite indicate? | That the compound contains some oxygen but less than a compound ending in -ate. |
| What do the prefixes hypo- and per- indicate? | Hypo- means the least amount of oxygen. Per- means the maximum amount . |
| What is a molecule? | Molecules are formed between non-metal elements. |
| What is a covalent bond? | When the electrons in the valence shell are shared between the atoms so that they can complete their valence shells and become stable. |
| What are the diatomic molecules? | Oxygen, Chlorine, Iodine, Bromine, Fluorine, Nitrogen, Hydrogen. |
| What are some properties of ionic substances? | High melting points as the electrostatic attraction between ions in the lattice is very strong. Hard due to the ionic bond. Never conduct electricity when solid as there are no free ions. However in a pure liquid, ions are free to move and carry a current and conduct electricity. |
| What does electrostatic mean? | The attraction between positive and negative charges. |
| What are some properties of molecular substances? | Low melting points. Solids are often soft. Never conduct electricity except sometimes in solution when dissolved as molecules react with water forming ions. |
| What does intermolecular mean? | The attractive force is an attractive force between molecules. It is much weaker than ionic, covalent and metallic bonds. It is what is broken when a molecule either melts or sublimes. It is weak so only a small amount of energy is needed. It is the reason why a lot of molecules are gases at room temperature. |
| Physical properties of ionic substances? | High melting point because the attractive forces between the ions are very strong. Strong forces between ions make ionic solids hard. Ionic solids don't conduct when solid because the ions are held in a fixed positions. However, when melted the ions are free to move and carry the current. |
| Physical properties of molecular substances? | Weak force between molecules, meaning only a small amount of energy is required to seperate them. This also makes molecular solids soft. Molecular solids do not conduct because they do not contain any charged particles free to move, even when melted. |
| Why do solid metals conduct? | Solid metals conduct because their outer electrons are free to move throughout the structure. |
| What are delocalised electrons? | When atoms of metals bond together in the solid state, one or more of their valence shell electrons becomes detached from each atom (decolonisation) and are free to move throughout the metallic structure. |
| What is metallic bonding? | The attraction between delocalised electrons and the positive metal ions (cations). The metallic bond is non-directional. |
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